At present, as an input medium, a touch screen is an easy, convenient and natural device for human-computer interaction. It has become a research and development focus for more and more flat panel display manufactures to integrate a touch function into a Liquid Crystal Display (LCD) or an Organic Light-Emitting Diode (OLED) display.
In recent years, in the field of display, an in cell Touch display Panel (in cell TP) was developed to further reduce the volume of a touch screen, so as to reduce the size of a mobile terminal having the touch screen. For the in cell TP, touch electrodes are integrated into a liquid crystal display panel. Therefore, a touch screen in which the in cell touch display technique is adopted may have a smaller size than a touch screen in which a One Glass Solution (OGS) is adopted.
In the conventional in cell TP, a common electrode in a pixel region doubles as touch electrodes, and thus the volume of the in cell TP can be reduced. However, in a case that a picture is displayed on a liquid crystal display panel, the common electrode is prone to be affected by a feed-through voltage generated due to a change in a gate electrode drive signal, resulting in a big noise in an output waveform of the common electrode, and further resulting in display abnormities in some display pictures, such as a ripple effect in a grayscale picture, thereby affecting the experience of a client. In this case, the precision of touch sensing may be decreased in a touch sensing phase if an existing filtering method is used to reduce the noise.
Therefore, the issuses are how to reduce the noise in the output waveform of the common electrode, how to improve the quality of a display picture and how to improve the precision of touch sensing.